A wild flip in the pattern on the way!

Who out there has enjoyed the record warmth of late? Who has noticed how dry it has gotten in the Mid-Atlantic region? Who is ready for a wild change in the pattern?

I’m sure many of you out there have enjoyed our mild winter and very warm start to Spring, but brace yourselves as things are going to get bumpy in the next 24 hours. I will write a post in the near future that will discuss just how warm and dry it has been in the Mid-Atlantic, while parts of the Gulf coast have received some much need reprieve from the drought conditions. Florida is even getting into the act and may seem some violent thunderstorms later today into tonight.

The short version of the forecast for the Mid-Atlantic: Expect some showers and thunderstorms this evening with a lull in rainfall overnight. Rain will move back into the area during the late morning on Sunday and will get heavy at times with possible thunder. Expect winds to increase as well. The heaviest rain will move out during the overnight on Sunday, then it gets much cooler and windy into Monday. Do not be surprised to see snowflakes on Monday in the DC and Baltimore areas, but it might be tougher to see this into NJ and NYC. I expect there to be some coastal flooding, wind gusts up to 60 mph or higher, and possible flooding from heavy rain.

Technical version:

The 12z GFS valid at 8 pm EDT on 04/22 showing sea-level pressure and 6-hour accumulated precipitation.

I decided to show the GFS today due to it’s close agreement with the NAM. The 36 hour forecast from the 12z GFS shows the low center deepening near the mouth of the Chesapeake Bay with a pressure less than 996 mb. This will provide some decent wind 30-40 mph along the coastal areas by evening with heavy rainfall. An axis of very heavy rain will be very near the DC-Baltimore metro areas.

The 12z GFS valid at 2 am on 04/23 showing sea-level pressure and 6-hour accumulated precipitation.

Six hours later, the low have moved into the Delaware Bay with a pressure below 992 mb. As the storm deepens (and it could do so more than the models suggest), I think it’s possible we could see winds exceed 50-60 mph along the coast with high gusts even making it inland. This will cause problems along the coastal areas with high waves, coastal flooding, and some possible tree damage.

But. . .there’s more. . .

Day 1-2 Precipitation forecast from the Hydrometeorological Prediction Center.

The above map shows the axis of heaviest rainfall along the immediate Mid-Atlantic coast. The DC-Baltimore area will see 1″-2″ of rain, while the Delmarva, NJ, and Long Island into western New England could see amounts exceed 4″!

Day 3 snowfall potential from the Hydrometeorological Prediction Center.

And of course, we can’t have a late season nor’easter without some snow. The HPC map above shows a large area of WV, western PA, and western NY that will see amounts greater than 4″, with some areas exceeding 12″ in the higher terrain. Looking at the model snowfall amounts, areas along the St. Lawrence River in Canada could get a tremendous snowstorm with amounts nearing 18+”.

Who said winter is over?!

Day 1 severe thunderstorm outlook from the Storm Prediction Center.

The SPC Day 1 severe weather outlook shows most of the peninsula of Florida under a slight risk today. There is a 5% tornado threat, but if there is any heating in the next few hours ahead of the strong low moving through the Gulf, this threat could increase. There is also a wind threat from the Mid-Atlantic down to Florida with afternoon thunderstorms today.

Get ready for a wild ride the next 24-48 hours!

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